Defer need-check-nil and clean up stale suppressions

emmylua deserialises an unknown diagnostic code to a catch all that
matches no checker, so every `invisible`, `nil-check` and
`global-element` suppression was silently doing nothing. Renamed to the
emmylua codes. `name-style-check` has no equivalent and is dropped, it
was already disabled under luals.

The `get_tile` suppressions referenced an api typedef bug from 2024
which no longer reproduces.

need-check-nil is deferred rather than disabled on merit: a third of the
407 findings come from MapPosition and BoundingBox being aliased as
`struct|[double, double]`, so every `entity.position.x` reads as
possibly nil. The rest need per site knowledge of runtime invariants.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

exp_gui/module/toolbar.lua

@@ -29,7 +29,7 @@ Toolbar.on_gui_button_toggled = script.generate_event_name()
 --- @class _ExpElement._prototype
 --- @field on_button_toggled ExpElement.OnEventAdder<EventData.on_gui_button_toggled>
 
---- @diagnostic disable-next-line: invisible, inject-field
+--- @diagnostic disable-next-line: access-invisible, inject-field
 function ExpElement._prototype.on_button_toggled(self, handler)
     return self:on_event(Toolbar.on_gui_button_toggled, handler)
 end